Studies of the Thermodynamics of Some Native and Ruthenated Metalloproteins by Spectroelectrochemistry

Author: Chiang, Huey-jenn

Year: 1987

Degree: Dissertation (Ph.D.)

Advisor: Gray, Harry B.

Committee Members: Gray, Harry B.; Collins, Terrence J.; Hopfield, John J.; Marcus, Rudolph A.

Option: Chemistry

DOI: 10.7907/8fcf-kt72

Abstract

The thermodynamic parameters of redox centers in some metalloproteins have been investigated using spectroelectrochemical techniques, with the employment of an OTTLE (Optically Transparent Thin-Layer Electrode) cell. With the aid of various carefully selected mediators, the temperature dependence of the formal redox potentials of type I copper (blue copper) ions in Rhus vernicifera (tree) laccase, as well as in native and in pentaammineruthenium-modified azurins from Pseudomonas aeruginosa, have been measured. Similar experiments have been carried out for the heme site of cis-[Ru(en)2(OH)(His)]-horse heart cytochrome c (en: ethylenediamine; His: histidine). Cyclic voltammetry has been used to study the pH-dependence of the formal redox potentials of the appended ruthenium ion in cis-[Ru(en)2(OH)(His)]-horse heart cytochrome c. Finally, the synthesis and spectroelectrochemistry of sperm whale myoglobin reconstituted with [Ru(MpIX)(DMSO) dicarboxylic acid]- moiety (MpIX: mesoporphyrin IX; DMSO: dimethyl sulfoxide) have also been carried out.

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